The invention relates to detachable dampener rollers for printing presses.
Cylindrical, moisture-absorbent dampener rollers are used in printing presses, often in conjunction with other rollers, to apply a thin film of water, or of a water and alcohol solution, to printing plates to help prevent ink smearing. Generally, such dampener rollers are mounted on an oscillating arm that moves the roller back and forth from the water supply to the printing plate. When printing presses are stopped for any reason, the dampener roller often is pressed against the printing plate with substantial radially applied force, sometimes for a long period of time.
In many dampener roller applications, disposable moisture absorbent covers are used on reusable heavy, substantially solid, hard rubber cylinders. The cover can be a spirally wound layer of fabric (adhered by two-sided, spirally wound adhesive tape) or a water-shrinkable sleeve of paper (available from 3M) or of seamless knitted fabric (available from Jomac, Warrington, Pa.). When a cover wears out, the worn cover must be razored off carefully, to avoid damage to the roller, and a new one secured to the cylinder by winding or shrink-fitting.
Sorresso U.S. Pat. No. 3,919,754 and Swope U.S. Pat. No. 2,966,724 disclose speeding up the cover replacement process by adhering moisture absorbent covers to disposable cardboard or plastic core tubes which are slid onto and off of permanent mandrels of the printing press. Sorresso discloses a seamless cover glued to a thin core tube that is detachably mounted on a hollow metal support tube between end caps having bearings mounted on a shaft of the printing press. Swope discloses spirally-wound covers glued to thicker core tubes that are detachably mounted on disposable end cap inserts or on a printing press shaft between end caps secured (one by a radial set screw) to the shaft or on a hollow support tube between end caps (one of which is secured to the support tube by axial screws) that are mounted on the printing press shaft.